Conversion of methylamine to olefin or mixture of olefins

Abstract

Convert a methylamine (e.g. monomethylamine, dimethylamine and trimethylamine) to a mixture of olefins (e.g. ethylene, propylene and butylene) by placing the methylamine, optionally in a mixture with at least one of ammonia and an inert diluent, in contact with a microporous acidic silicoaluminophosphate catalyst or a microporous aluminosilicate catalyst.

What is claimed is: 
     
       1. A process for preparing an olefin, comprising placing at least one methylamine selected from monomethylamine, dimethylamine and trimethylamine, in a mixture with ammonia and methane in an amount sufficient to reduce the ratio of ethylene to propylene in the mixture of olefins and, optionally, an inert diluent, in contact with at least one microporous acidic silicoaluminophosphate catalyst or microporous aluminosilicate catalyst under conditions of temperature, pressure and weight hourly space velocity sufficient to convert at least a portion of the methylamine to a product stream comprising a mixture of olefins that comprises ethylene, propylene and butene. 
     
     
       2. The process of  claim 1 , wherein the temperature is within a range of from 400° centigrade to 700° centigrade. 
     
     
       3. The process of  claim 1 , wherein the pressure is sufficient to provide a total system pressure of from greater than or equal to 0.1 bar (10 kilopascals) to 60 bar (6 megapascals). 
     
     
       4. The process of  claim 1 , wherein the weight hourly space velocity of methylamine is within a range of from 0.1 grams of methylamine per gram of catalyst per hour to 50 grams of methylamine per gram of catalyst per hour. 
     
     
       5. The process of  claim 1 , wherein diluent is present in a mole ratio of diluent to methylamine that falls within a range of from greater than or equal to 0:1 to 20:1. 
     
     
       6. The process of  claim 1 , wherein the catalyst is selected from a group consisting of SAPO-34, H-ZSM-5, offretite, mordenite, 13X, and ferrerite. 
     
     
       7. The process of  claim 1 , wherein the at least one methylamine comprises a mixture of two or more of monomethylamine, dimethylamine and trimethylamine, the mixture having a carbon to nitrogen atom ratio greater than that of monomethylamine alone, whereby selectivity to a combination of ethylene and propylene is greater with the mixture than selectivity to such combination of ethylene and propylene based upon use of monomethylamine as a sole methylamine. 
     
     
       8. The process of  claim 1 , wherein at least a portion of ammonia, unreacted methylamine and, when present, diluent is recycled and mixed with fresh methylamine before the methylamine contacts the catalyst. 
     
     
       9. The process of  claim 1 , wherein the temperature is within a range of from 450° centigrade to 650° centigrade. 
     
     
       10. The process of  claim 1 , wherein the pressure is sufficient to provide a total system pressure of from 1 bar (100 kilopascals) to 5 bar (500 kilopascals). 
     
     
       11. The process of  claim 1 , wherein the weight hourly space velocity of methylamine is within a range of from 0.5 grams of methylamine per gram of catalyst per hour to 5 grams of methylamine per gram of catalyst per hour.